Rats can multiply quickly; a few rapidly becomes hundreds. Zach Cirus, Quality Manager at Colonial Pest Control, talks about how to rid your home and yard of rats. Listen or read more to find out the best rat removal procedures.

John Maher: Hi, I’m John Maher. I’m here today with Zach Ciras, Quality Manager with Colonial Pest Control. Today our topic is rats in New England homes. Welcome, Zach.

Zach Ciras:  Thanks, John.

John: So, Zach, I understand that rat populations in suburbs have actually been increasing recently. Do we know why?

Zach: They sure have, and I would love to have a very good scientifically sound answer for you. I don’t. The population’s been increasing, but populations of most wildlife, including rats and mice and birds of prey and coyotes and wolves, everything’s been increasing around us, at least from when I’ve been able to see. I live in south central Massachusetts, and you know population’s high when you see roadkill. And I have been seeing coyotes on the side of the road, so that shows that the population’s increasing. As far as why the rats are increasing, I don’t really know. I know for mouse populations, there was a big boom 2016, 2017. There was a huge acorn drop. So, the mice had food for years.

John: Oh, that’s interesting.

Why is There an Increase in the Rat Population?

Zach: We’re starting to see them come down a little bit, but from ’16, ’17, they’ve stored all those acorns and there’ve been living off of those acorns for a long time and the population boomed for them. I can’t find a correlating reason for why the rats are increasing like they are. There are some thoughts. Just a random thought one of our distributors had the other day, like, ‘Well, I haven’t really had any calls for feral cats lately.’ I don’t know. South Shore, there’s still a lot of feral cats, maybe not in the cities as much as there used to be, but I don’t see that type of correlation with that.

John: Yeah, I mean, it is true that a lot of people have indoor cats now because having outdoor cats, they say that it shortens their life and they’re much more likely to have accidents or get killed and things like that, so a lot of people are keeping their cats inside now, so it could possibly be part of it.

Zach: It could be part of it. The sanitation on the streets is usually one of the more driving factors. On the west coast, some of the major cities there have a higher homeless population, less cleanliness, less sanitation on the streets. I’m thinking San Francisco and LA and Baltimore and New York, on the east coast. Boston actually isn’t too bad, so we’re pretty good in Massachusetts as far as ranking of the highest rat pressure, but the pressure is increasing, especially around the suburbs.

And rats are scavengers. So, if there’s any kind of trash on the food, any kind of litter or garbage on the food, if there’s excrement, whether it’s human or dogs and cats or other wildlife rats will take advantage of any nutrient source they can get their hands on. And they also need a lot of water. So, wherever there’s water, you’re going to find rats. There’s a, I think it’s a Chinese proverb that says, ‘Where there are people, you will find rats and Buddhas.’ So, there’s always going to be rats around to kind of clean up the mess that we make, our pets make, and all that. As far as the big boom we’ve seen lately, the last couple of years, especially, I don’t have a clear definition or why.

Clean Homes and Yards are Unattractive to Rats

John: Right. It’s interesting. So, are cities and towns doing anything on a wide scale to try and curb the problem? I know that my family and I, we recently visited a friend of ours whose daughter is at a school down in Rhode Island and we went to a big park down there and there were signs that said, ‘We’ve removed all of our trash cans from this whole park and please just anything that you bring in, just take it home with you and throw it away at home.’ And I couldn’t think of, ‘Well, why would that be other than just that they don’t really feel like coming and cleaning out the trash cans and having to do all of that extra work to pick up after people?’ But maybe they’re actually doing it to try to not have trash sitting out in their public park all the time that could attract rats and things like that.

Zach: That’s interesting. Yeah. That would make sense. I haven’t seen that case specifically, but they do it for bears. We were out on the west coast last year hiking around the mountains up there and there’s those bear-safe trash containers that keep the bears out, so it would make sense that rats, which are pretty crafty on their own, did find a way to into the trash receptacles in a park. Cities and towns are making those kinds of efforts.

Sanitation is huge, huge, huge for rats. So, anything the city can do or anything that the city or state or any government can do to inform the population that, ‘Hey, you’re responsible for this as well. You need to make sure that whatever you’re bringing in, you’re taking out,’ just like the old Boy Scout thing, whatever you bring in, you need take out, cleaning up after yourselves, making sure that the trash is not put out on Monday if trash day is Thursday, it’s put out Thursday morning or Wednesday night. All those little things help. It doesn’t seem to take much when you get a population increasing, increasing, to get to the tipping point. Once you’re close to the tipping point, any small factor can really flip it to where it’s overwhelming, an overwhelming population once they’ve tipped. So, sanitation, trying to prevent the habitat that would breed rats at a higher level, that’s really important.

Another thing that cities and towns are doing, I’m not sure if they’re doing it as effectively as they could, is doing their own pest control, maintenance kind of program where they’re actually trying to eliminate a rat population. The standard that cities especially do with central sewer systems is do sewer baiting, so they take moisture-resistant anticoagulant rodenticide baits, they lower them down into the sewers and they kind of cross their fingers and hope that the rats are going to start chewing on them and eliminate some of the rats that are eating the baits and try to control the population that way. It’s not terribly effective. It might be the best we have right now, but it’s not terribly effective.

Another means that has been in trials for the last year or so has been, there’s a product on the market now, which essentially, it’s birth control for rats. It’s a specific rodent birth control. It’s only labeled for rats, but it would work for rats and mice and other rodents. And it’s a very short half-life, so it’s not as worrisome to have that much birth control in the environment. We already have enough of our own controls and our own medicine into the sewer system, into the environment, so we don’t need to add on something that is intended to control a rat population causing another problem.

So, the problem with that is two-fold. One is they have to eat it. They have to consume it. It’s kind of like a slurry protein shake kind of mix. So, the idea, rats need to eat about 10% of their body weight every day and they need to consume a large amount of water, so give them something that’s tasty, that gives them a lot of nutrients and that’s water-based, and they should eat it. They haven’t quite gone to it yet. It’s tough to get them to eat something that you want them to eat rather than them finding something on their own that they’re more comfortable with.

And the second reason this isn’t as effective, at least so far, as we would hope is they need to continuously feed on the birth control. And if they stop feeding on it, it stops being effective. The whole idea of the birth control is not to kill the rats that are feeding on it, but it’s really just to diminish the population or decrease the population through attrition. The life out in the wild for an animal, it’s a cruel world out there. Rats can live up to four years on their own, but out in the wild, they really average closer to two. And that’s not necessarily taking into account the young that don’t quite make it, the dominant males that are defeating the submissive males and taking over their territory and kind of weeding out the population on their own. It’s a brutal world down there.

But through attrition, the idea is if you don’t let the rats reproduce, then you’ll have fewer rats. And it makes sense. You could see the population really plummet within two to three months. You have almost a month for gestation period. You could have an average of about 9 or 10 pups per litter, and they can go even more than that, maybe 14 pups per litter if the conditions are good. So that would really help decrease, but between the baits and the birth control, it doesn’t seem to be having the same effect as it has for 20, 30 years and they’re used to it.

So, I think cities and towns as well need to make some adjustments in how they’re dealing with the larger rat problem, because once the rats are running through our customer’s backyards and the parks across the street and then digging down and getting into the home and finding the openings and getting into the chicken coops . . . that’s another reason why rat populations might be increasing. So many people in urban and suburban areas have their own chickens now. They love the farm fresh eggs. They like teaching the kids how to take care of something that’s not just the family dog. They have to feed and water and clean up.

So, it’s a great thing, but chickens and birds in general are very messy eaters, and there’s a lot of extra stuff that goes around that could be very attractive for rats, so giving them more reason to be in the area, more reason to breed in that area if the resources are good. There’s a lot of factors that go in, and I think everybody from the city and town to the individual, we all need to make a more concerted effort to really think better about how to control the rat population before it gets too much.

Rat Populations Grow Fast

John: Right. That’s really interesting. And in terms of the population and using that birth control that you were talking about, I don’t know if you know exactly, but after the babies are born, the rat babies, the pups that you said, I think it’s only a few months later that they’re old enough that they can have babies of their own. Is that right? They don’t have to be very old at all.

Zach: No, they don’t have to be very old at all. It’s only a few weeks before they’re weaned off and their maturity is not much more after that. So, you could have a three-month-old rat breeding again with another gestation period of 22 or 24 days, so it could really take over in a hurry.

John: Yeah. That’s why it just explodes is the population, like you said, can just explode so fast from just a few rats to thousands of rats very, very quickly.

Zach: I’m currently dealing with one house in Worcester that I pulled out three at a first visit, doubled the efforts, pulled out 10 a week later, and I know that there’s more in there. I could actually hear them kind of grunting. This house for a long time had just piles of trash on one side of the house, overgrown vegetation on the other side of the house. The basement is filled with litter, old mattresses, old toys, piles of junk, and it’s a Fieldstone foundation that has not been reappointed in a long time and really needs some serious effort. And this Worcester house, just the woodwork on the inside and the living area is gorgeous. You can’t make this stuff anymore. People spent a lot of time and effort years ago to make a beautiful inside, but from the foundation level into the basement, it’s just rat heaven.

Keeping Your Home Rat-Free

John: Wow. So, you bring up a point, which is my next question was going to be, did the rats get into people’s homes, and what can an individual homeowner do to help prevent rats from getting into their house?

Zach: Yeah. So, in pest control in general, the first thing we need to do is to identify and make sure that we are dealing with rats, because a lot of folks, especially the translation from other languages, they might not have specific words to differentiate rats and mice. So, a mouse is just . . . say, Spanish, the word for mouse is just little rat, so make sure that we’re dealing with rats because you have to approach rats and mice very differently. Mice are very neophilic. They like new things. They’re curious for the most part. Some of these deer mice are giving us a run for our money, but for the most part, they’re curious. You put out some snap traps with some tasty food on it. They go, “Oh, what’s this?” And then we got them, or some baits, the bait station. “Oh, delicious food. Where’d this come from? What joy.”

Rats are very neophobic. New things, new snap traps, new controls, new bait stations, new protein shakes that might have birth control in them, anything that’s new, rats really are very wary of, to the point where we’re even re-baiting our snap traps with tasty things like Slim Jims or bacon or chocolate to get the rats to eat from the traps before they’re set so that they’re comfortable enough, when we do come back and set them, hopefully we’ll get a big yield out of that. And that’s what happened in that Worcester house.

John: Yeah. So you’re making sure that they’re comfortable going into the trap, eating the food and then they look at it as not being a scary thing, but as a place where they’re used to getting food and then you set the trap, put the bait back in there, and then you’ve got them the next time.

Zach: Yeah. So, we want to identify if it’s rats. After that, the next thing we always consider is habitat alteration. What do we need to do with the habitat to make it less inviting for rats? Is there clutter? Is there litter? Are there food sources around? Is it a bad foundation? Do we need to do some exclusionary worked to help prevent the rats from coming in in the first place? What kind of changes can we make inside to make it less attractive? So, the habitat alteration is always next, then we make a plan. Rats, you really need to plan it out. You can’t just put out some traps or put up some baits and cross your fingers and expect that that’ll take care of it.

As far as what a homeowner can do, keep it as clean as possible. Keep it as litter-free as possible. If there’s a possibility that rats can hide in or around your house, you want to eliminate that to whatever degree you can. So, if there’s overgrown vegetation, shrubs, ground cover, piles of stones . . .  my neighbors actually did some work. They put in a new garage last year. So, in the Blackstone Valley, there’s a lot of . . . the soil is mostly rocks. So, there’s a big pile of stone rocks that are just piled up in between their house and our house. And if we have rats coming in, I know where they’re going to hang out. They’re going to find those rocks and make some burrows into there. So, trying to prevent harborage area is really crucial, as well as the sanitation to remove potential food sources.

One of the big problems that we do see when we’re trying to control a rat population, especially around the exterior perimeter of a house where there’s a dog or dogs in the neighborhood, is the dog droppings, the dog poop. Dogs, the food that we give dogs especially is very grain-based or a lot of rice and corn and filler, rather than just, ‘Here’s some meat.’ Dogs biologically in the wild, they are eating meat, primarily eating meat. So, when we give them a lot of corn and filler, those nutrients that are in the corn field, the long gene starches, the sugars, those don’t get metabolized by the dog. They just get deposited into the yard.

And if you’re not really good about picking that up every time, then the rats will find that. And as gross as it is, the rats will be very happy. They’re a bit like pigs in that same matter. They’ll go over to the droppings and if they’re looking at dog poop that’s been there for a number of years that they’re used to eating versus a black plastic box with some grain and wax mixture inside of it for our bait station, they already know the dog poop is safe, so they’re going to go to that and not our bait station. So, removing the competing food sources, even to the point of the dog food or the weeds that have the berries on them, all that kind of stuff, removing that as competing food sources will help us control the rats by giving them no choice but to eat our bait.

Contain Your Trash to Contain the Rat Problem

John: That’s really interesting. Yeah. Do you ever recommend to people . . . I know that you mentioned before that when people take out their trash, and that particular house in Worcester that you mentioned had a lot of trash that was outside, do you recommend that people find a place inside the home for them to store their trash during the week and then only put it out just right on trash day, or is there anything else that people can do to kind of keep the outside of their home cleaner in terms of trash?

Zach: [crosstalk] Sesame Street had Oscar the Grouch and Oscar lived in that metal trash can, and he always had the lid on it. When he popped up, that was his hat. So those metal containers do a really good job keeping animals out, rats and squirrels. A squirrel is not too far off behavior-wise and even looks-wise than a rat with a fluffy tail that goes up in the trees.

So, rats and squirrels will chew through even the plastic containers. The ones that your trash collection company gives you to put out, those are pretty easy for rats and mice to chew through. The enamel on a rat’s tooth is one of the hardest surface materials in the world. They’ll chew through a lead pipe or some copper pipes like it’s nothing. They have really strong teeth, so some plastic is very easy to get through. So those metal containers with the lid on nice and tight, those will do a great job keeping rats out of the food as well as squirrels out of the food. And then if you need to put it in the plastic bin the night before, it shouldn’t be too hard. Flip over the trash can, empty it into the plastic bin for the collection company to come and pick them up. But those metal containers on the outside, I think that’s the best way to go.

John: That’s really good advice. All right. Thanks, Zach. I appreciate your time today.

Zach: Thanks, John.

John: And for more information, you can visit Colonial Pest Control’s website at colonialpest.com or call (800) 525-8084. That’s (800) 525-8084.